180 \cdot \frac{\tan^{-1} \left(\frac{\left(\frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} - \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) - \sqrt{{\left(\frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale} - \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale}\right)}^{2} + {\left(\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale}\right)}^{2}}}{\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale}}\right)}{\pi}180 \cdot \frac{\tan^{-1} \left(\frac{\left(\frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} - \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(\cos \left(\frac{angle}{180} \cdot \pi\right) \cdot b\right)}^{2}}{x-scale}}{x-scale}\right) - \sqrt{{\left(\frac{\frac{{\left(\cos \left(\frac{angle}{180} \cdot \pi\right) \cdot b\right)}^{2} + {\left(a \cdot \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right) - 2.8577960676726107 \cdot 10^{-08} \cdot \left({angle}^{3} \cdot {\pi}^{3}\right)\right)\right)}^{2}}{x-scale}}{x-scale} - \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \log \left(e^{\sin \left(\frac{angle}{180} \cdot \pi\right)}\right)\right)}^{2}}{y-scale}}{y-scale}\right)}^{2} + {\left(\frac{\frac{\cos \left(\frac{angle}{180} \cdot \pi\right) \cdot \left(\sin \left(\frac{angle}{180} \cdot \pi\right) \cdot \left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right)\right)}{x-scale}}{y-scale}\right)}^{2}}}{\frac{\frac{\cos \left(\frac{angle}{180} \cdot \pi\right) \cdot \left(\sin \left(\frac{angle}{180} \cdot \pi\right) \cdot \left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right)\right)}{x-scale}}{y-scale}}\right)}{\pi}(FPCore (a b angle x-scale y-scale)
:precision binary64
(*
180.0
(/
(atan
(/
(-
(-
(/
(/
(+
(pow (* a (cos (* (/ angle 180.0) PI))) 2.0)
(pow (* b (sin (* (/ angle 180.0) PI))) 2.0))
y-scale)
y-scale)
(/
(/
(+
(pow (* a (sin (* (/ angle 180.0) PI))) 2.0)
(pow (* b (cos (* (/ angle 180.0) PI))) 2.0))
x-scale)
x-scale))
(sqrt
(+
(pow
(-
(/
(/
(+
(pow (* a (sin (* (/ angle 180.0) PI))) 2.0)
(pow (* b (cos (* (/ angle 180.0) PI))) 2.0))
x-scale)
x-scale)
(/
(/
(+
(pow (* a (cos (* (/ angle 180.0) PI))) 2.0)
(pow (* b (sin (* (/ angle 180.0) PI))) 2.0))
y-scale)
y-scale))
2.0)
(pow
(/
(/
(*
(*
(* 2.0 (- (pow b 2.0) (pow a 2.0)))
(sin (* (/ angle 180.0) PI)))
(cos (* (/ angle 180.0) PI)))
x-scale)
y-scale)
2.0))))
(/
(/
(*
(* (* 2.0 (- (pow b 2.0) (pow a 2.0))) (sin (* (/ angle 180.0) PI)))
(cos (* (/ angle 180.0) PI)))
x-scale)
y-scale)))
PI)))(FPCore (a b angle x-scale y-scale)
:precision binary64
(*
180.0
(/
(atan
(/
(-
(-
(/
(/
(+
(pow (* a (cos (* (/ angle 180.0) PI))) 2.0)
(pow (* b (sin (* (/ angle 180.0) PI))) 2.0))
y-scale)
y-scale)
(/
(/
(+
(pow (* a (sin (* (/ angle 180.0) PI))) 2.0)
(pow (* (cos (* (/ angle 180.0) PI)) b) 2.0))
x-scale)
x-scale))
(sqrt
(+
(pow
(-
(/
(/
(+
(pow (* (cos (* (/ angle 180.0) PI)) b) 2.0)
(pow
(*
a
(-
(* 0.005555555555555556 (* angle PI))
(* 2.8577960676726107e-08 (* (pow angle 3.0) (pow PI 3.0)))))
2.0))
x-scale)
x-scale)
(/
(/
(+
(pow (* a (cos (* (/ angle 180.0) PI))) 2.0)
(pow (* b (log (exp (sin (* (/ angle 180.0) PI))))) 2.0))
y-scale)
y-scale))
2.0)
(pow
(/
(/
(*
(cos (* (/ angle 180.0) PI))
(*
(sin (* (/ angle 180.0) PI))
(* 2.0 (- (pow b 2.0) (pow a 2.0)))))
x-scale)
y-scale)
2.0))))
(/
(/
(*
(cos (* (/ angle 180.0) PI))
(* (sin (* (/ angle 180.0) PI)) (* 2.0 (- (pow b 2.0) (pow a 2.0)))))
x-scale)
y-scale)))
PI)))double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
return 180.0 * (atan((((((pow((a * cos((angle / 180.0) * ((double) M_PI))), 2.0) + pow((b * sin((angle / 180.0) * ((double) M_PI))), 2.0)) / y_45_scale) / y_45_scale) - (((pow((a * sin((angle / 180.0) * ((double) M_PI))), 2.0) + pow((b * cos((angle / 180.0) * ((double) M_PI))), 2.0)) / x_45_scale) / x_45_scale)) - sqrt(pow(((((pow((a * sin((angle / 180.0) * ((double) M_PI))), 2.0) + pow((b * cos((angle / 180.0) * ((double) M_PI))), 2.0)) / x_45_scale) / x_45_scale) - (((pow((a * cos((angle / 180.0) * ((double) M_PI))), 2.0) + pow((b * sin((angle / 180.0) * ((double) M_PI))), 2.0)) / y_45_scale) / y_45_scale)), 2.0) + pow((((((2.0 * (pow(b, 2.0) - pow(a, 2.0))) * sin((angle / 180.0) * ((double) M_PI))) * cos((angle / 180.0) * ((double) M_PI))) / x_45_scale) / y_45_scale), 2.0))) / (((((2.0 * (pow(b, 2.0) - pow(a, 2.0))) * sin((angle / 180.0) * ((double) M_PI))) * cos((angle / 180.0) * ((double) M_PI))) / x_45_scale) / y_45_scale)) / ((double) M_PI));
}
double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
return 180.0 * (atan((((((pow((a * cos((angle / 180.0) * ((double) M_PI))), 2.0) + pow((b * sin((angle / 180.0) * ((double) M_PI))), 2.0)) / y_45_scale) / y_45_scale) - (((pow((a * sin((angle / 180.0) * ((double) M_PI))), 2.0) + pow((cos((angle / 180.0) * ((double) M_PI)) * b), 2.0)) / x_45_scale) / x_45_scale)) - sqrt(pow(((((pow((cos((angle / 180.0) * ((double) M_PI)) * b), 2.0) + pow((a * ((0.005555555555555556 * (angle * ((double) M_PI))) - (2.8577960676726107e-08 * (pow(angle, 3.0) * pow(((double) M_PI), 3.0))))), 2.0)) / x_45_scale) / x_45_scale) - (((pow((a * cos((angle / 180.0) * ((double) M_PI))), 2.0) + pow((b * log(exp(sin((angle / 180.0) * ((double) M_PI))))), 2.0)) / y_45_scale) / y_45_scale)), 2.0) + pow((((cos((angle / 180.0) * ((double) M_PI)) * (sin((angle / 180.0) * ((double) M_PI)) * (2.0 * (pow(b, 2.0) - pow(a, 2.0))))) / x_45_scale) / y_45_scale), 2.0))) / (((cos((angle / 180.0) * ((double) M_PI)) * (sin((angle / 180.0) * ((double) M_PI)) * (2.0 * (pow(b, 2.0) - pow(a, 2.0))))) / x_45_scale) / y_45_scale)) / ((double) M_PI));
}



Bits error versus a



Bits error versus b



Bits error versus angle



Bits error versus x-scale



Bits error versus y-scale
Results
Initial program 55.0
rmApplied add-log-exp_binary6455.0
Simplified55.0
Taylor expanded around 0 54.5
Final simplification54.5
herbie shell --seed 2021173
(FPCore (a b angle x-scale y-scale)
:name "raw-angle from scale-rotated-ellipse"
:precision binary64
(* 180.0 (/ (atan (/ (- (- (/ (/ (+ (pow (* a (cos (* (/ angle 180.0) PI))) 2.0) (pow (* b (sin (* (/ angle 180.0) PI))) 2.0)) y-scale) y-scale) (/ (/ (+ (pow (* a (sin (* (/ angle 180.0) PI))) 2.0) (pow (* b (cos (* (/ angle 180.0) PI))) 2.0)) x-scale) x-scale)) (sqrt (+ (pow (- (/ (/ (+ (pow (* a (sin (* (/ angle 180.0) PI))) 2.0) (pow (* b (cos (* (/ angle 180.0) PI))) 2.0)) x-scale) x-scale) (/ (/ (+ (pow (* a (cos (* (/ angle 180.0) PI))) 2.0) (pow (* b (sin (* (/ angle 180.0) PI))) 2.0)) y-scale) y-scale)) 2.0) (pow (/ (/ (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) (sin (* (/ angle 180.0) PI))) (cos (* (/ angle 180.0) PI))) x-scale) y-scale) 2.0)))) (/ (/ (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) (sin (* (/ angle 180.0) PI))) (cos (* (/ angle 180.0) PI))) x-scale) y-scale))) PI)))